This suggests that there is an issue with the installation of the Extension Manager. I have seen a problem similar to this a couple of times. Basically, in your case, the extension manager is installing into two places. When you double click an extension and open the extesnion manager that way, it is not actually installing into Dreamweaver Only when you open the extension manager through Dreamweaver does it install the extension in Dreamweaver. To resolve the issue, you will need to contact Adobe support.
Untill you have resolved the problem with the extension manager, you will need to manually perform the install or uninstall of extensions to make sure you are using the correct one. The correct one is the one that you open through Dreamweaver.
try renaming the configuration folder once again. Then open the extesnion manager through Dreamweaver, close Dreamweaver before proceeding, then remove the extension, once removed install them again, this will ensure that the new installation is actually effecting Dreamweaver.